1. Field of the Invention
The present invention relates to snap locks in general and, more specifically, to snap locks for sliding windows and doors.
2. Description of the Prior Art
The particular class of latches to which the present invention pertains uses latching plates with latching shoulders, between which a land to provide an abutment is formed. The latching shoulders are inclined with respect to a vertical surface of a window frame. For example, U.S. Pat. No. 5,901,501 dated May 11, 1999 and granted to Fountaine for a xe2x80x9cWindow Fastenerxe2x80x9d describes a lock for use with a sliding sash window. The lock has a body with a handle mounted with the body for pivotal movement about a pivot axle. A latch tongue is operatively coupled to the handle and a latch tongue is provided with a latching surface for contacting an end of the latch tongue. The latching surface is spaced from the pivot axle in the direction in which a sash of a window is movable from a closed position relative to the frame of the window. The handle is movable about the pivot axle to move the end of the latch tongue away from its latching contact of the latching surface of the latch plate. Thus, the window sash can be moved from the closed position. Fountain""s xe2x80x9cWindow Fastenerxe2x80x9d has several important shortcomings. First, the latching tongues are moveable independent of each other and of the handle. Second, limited pivot movement of the tongues by the handle. Third, sliding action is not rectilinear.
Based on the analysis of the prior art, there is a need for a snap lock which eliminate or, at least, alleviate the foregoing shortcomings.
A first objective of the present invention is to provide a simple and reliable snap lock.
A second objective of the present invention is to provide a snap lock with a rectilinear movement of the latching element.
A third objective of the present invention is to provide a snap lock held in an open position while the sliding window or door is open.
A fourth objective of the present invention is to develop a snap lock provided with alignment and security means.
A fifth objective of the present invention is to provide a snap lock with extended service life.
A sixth objective of the present invention is to provide a snap lock that satisfies the demands of technical aesthetics.
Broadly stating, the snap lock according to the present invention is adaptable to be secured to a sash of a sliding window or door and to interact with a striking plate having horizontal and vertical plates and also adaptable to be secured to a frame of the sliding window or door. The snap lock comprises stationary lower and upper plates for capturing between them a rectilinearly mobile plate for locking the snap lock with respect to the striking plate. The snap lock includes as well:
a three-point pivoting mechanism for interconnecting the foregoing plates and, thereby, enabling to perform an unlocking operation;
a springy feature for keeping, when relieved from tension, the rectilinearly mobile plate for locking the snap lock with respect to the striking plate in an unlocked, retracted position, and when under tension, for keeping the rectilinearly mobile plate for locking the snap lock with respect to the striking plate in a locked, forwardly protruding position, the springy feature being attached to the stationary lower and upper plates for capturing and being actuated by a contact with the vertical plate; and
a cover provided with an aperture for locating and accessing a button for acting upon the three-point pivoting mechanism for interconnecting.
According to one aspect of this invention, the springy feature for keeping, when relieved from tension, the rectilinearly mobile plate for locking the snap lock with respect to the striking plate in an unlocked, retracted position, and when under tension, for keeping the rectilinearly mobile plate for locking the snap lock with respect to the striking plate in a locked, forwardly protruding position, includes a pair of flat springs. Each of said pair of flat springs has basically a U-shape and is provided with a short lower and long upper arms. The short lower arm extends laterally into an eyelet adapted for inserting a rivet that is eventually forced into flat spring holes and corresponding flat spring holes disposed in the stationary lower and upper plates for capturing. The long upper arm continues downwardly and perpendicularly at one side with a double bent end and at another side with a cantilevered end located besides the double bent end.